DISCLAIMER: I have no association with UVB-76 station, neither do I have any clue what is the content I am relaying. I can only assure, that the signal is received on 4.625MHz AM-modulated 900km NW from supposed origin and retransmitted unaltered. In no way can I guarantee this service, nor be considered responsible of any content re-transmitted. The only purpose for this relay to exist is because lot of people who do not have equipment or are located too far from station seem to be interested about listening to it. Should the UVB-76 station- or transmission content owners feel violated in any way, please contact me at uvb76.repeater@gmail.com and we will work it out.

Note, that because of shortwave radio signal propagation specifics the station can be more or less reliably received from around 4pm to 6am GMT on summertime. It is almost 24h audible during the winter, with short "skip-zone" blank-out around 6pm GMT.

The USB feed is considered as main source of audio today, as the voice messages are much better audible there than on the AM stream. However, the buzzer sound from the AM stream is somewhat more pleasant to listen at, so both feeds are kept simultaneously.

Friday, February 25, 2011

SDR MK1 Shortwave Radio Shematic and Layout Update

The SDR MK1 project page has been updated with new schematic (v1.02) and has now also a layout with some explanations about what and how.

The PCB-s went already to production and I expect the boards and components arrive some time next week, so the moment of truth is quite near :) (Although the software will likely take several more weeks t polish).

As a sidenote, I just realized that having the dual channel shortwave software radio may be a nice thing, but having another channel tuned on utility frequency range would make it even nicer tool locally. With appropriate bandpass filter, we can nicely tune from 144MHz amateur band up to the 174MHz TV ch.7 with our 30MHz spectrum width, so it covers most of the open utility channels.

Guess I have to start designing a filter boad! :)

Wednesday, February 23, 2011

First version of the layout ready

Just for your amusement, this is what the PCB layout for SDR MK1 looks like! I will update the project page later on (new revision of the schematic etc.), this is just a quick glimpse.
The design is done to fit the milled housing, so its only 106x78mm in size ;)

Tuesday, February 15, 2011

Justin.tv ads

Please receive my apologies for the audio-visual ads you receive every time the front page is loading. Justin.tv has recently decided to cash in and while I have no objection of them doing so, it is extremely annoying to have such thing happening on a blog front page.

It will take some time (weeks, rather than months tho) to configure my own video streaming server up and running stable (I have tried at least 5 different webcam services, none of which are really suitable for unattended video streaming), so please try to cope with the situation meanwhile ..

SDR MK1 Housing

SDR MK1 housing just arrived! Big thanx to my brother, who did the CAD drawings and organized the manufacturing!

As a result, SDR MK1 is going to live inside 110x80mm solid milled aluminum block! It costs 70EUR to manufacture, but somehow it feels like money well spent! :)

It seems, that the SDR MK1 is more and more becoming an open source product of a sort, where one can build it totally on his own, order a bare PCB, order a PCB with some (difficult to assemble) components mounted and rest in a anti-static bag, order an populated board without an housing or have a complete radio delivered.

However, first I have to get the prototype running! Currently the PCB component placement is done and about 70% of routing is finished. I am still working with only two layers, so there is hope, but at least one area looks really tough at the moment (thank you National Semiconductor, for positioning three different power buses and internal analog filter caps all at the same side of the 128pin housing!!!), so it may end up with four layer board instead. 

Here are some pictures of the housing. Note, that it still has to go through glass-balling and anodizing to get this satin Apple-like look. At the moment it is as it came from the milling.

Sunday, February 6, 2011

SDR MK1 Preliminary Schematic

After several weeks in making, the first version of the SDR Mark1 schematic is finally here. Look at the SDR Project page, click "Schematic" at the index on left.

It may be a right time to apologise for the statements made earlier as "simple", "easy"  etc! :))
While in fact its not too complicated considering what it is about, I ended up with way more components than initially planned.
On the other hand, it has no cut-backs anywhere, so I can state that it is as good as my current knowledge of SDR design allows me to create.

Now to the PCB layout and then we shall see if it performs as supposed to!